Update Paypal config form to show sandbox option.
Checking for upload error number rather than text match

Check the $_FILES array for an error number rather than attempting to
match the language based error.
Removed legacy tablerate shipping method
Replace ajax based category picker with a category tree

Due to many complaints about the category search in the product form
page, it's been replaced with a much simpler category tree.
updated
Made step_1 of checkout utilize translated field names
update
Merge branch '2.0-Development' of https://github.com/gocart/GoCart into 2.0-Development